Bulgarian girls names?

I read somewhere else that wrong names were big nuisance, so I thought I'd double check that the foreign names I've used are in fact from the right country.
I got the names from online, so if it's actually foreign for something offensive or anything like that, I apologize.
The main concern is three Bulgarian girls. Bilyana, Ralica and Nevana. They are 15, 12 and 8, born and named in a rural part of the country, and the story takes place no earlier than 1977. They are siblings, in case that matters to the naming.

Thanks in advance for any help verifying the legitimacy of the names. =)

I have met three people from Poland, Romania and Spain in the last year alone who all had names that were non-traditional to their countries. Not everyone has traditional native names and although I am not saying we should ignore native names, I think people sometimes too obsessive with them. The name of a great Russian character,a killer, in a book I read two or three years ago was "Tommy". And it worked brilliantly. It's the story and character that matter imho.